This invention relates to an automatically-controlled water faucet of the type using automatic detection means for controlling the water supply from the faucet. One of the difficulties with this type of faucet is designing it so it will respond to the presence or absence of a user but will not respond to other objects or activity, such as reflection from the sink basin, the water flow, or other extraneous signals. The design problems are further complicated by the desire to make the control reasonably sensitive to a user's presence at an operative position essentially beneath the faucet outlet.
Faucets having associated emitting and/or detecting means mounted to detect a user's presence are shown in U.S. Pat. Nos. 3,151,340; 3,415,278; 3,491,381; 3,505,692; 3,551,919; 3,585,652; 3,638,680; 4,398,310; 4,402095; 4,682,628; 4,604,764 and 4,709,728. None provide a concentrated zone of effective detection which is positioned optimally relative to the flow path from the faucet discharge.